I'd encourage op to file a DOT complaint with the boarding pass.

yesterday, I was on a PHX-ORD flight which was on time and still boarded 15 minutes earlier than the boarding pass time, so that when I reached the gate 5 mins after the printed time, the flight was "closing" already.

On AA's side they seem to treat posted times as a "guideline", never bothering to update them, even on for example obviously delayed flights. I think only DOT complaints are going to get them to do anything...